LTC3774
Dual, Multiphase Current
Mode Synchronous Controller
for Sub-Milliohm DCR Sensing
FEATURES DESCRIPTION
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Sub-Milliohm DCR Current Sensing The LTC 3774 is a dual PolyPhase current mode syn-
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Operates with Power Blocks, DRMOS or External chronous step-down switching regulator controller that
drives power blocks, DRMOS or external gate drivers and
Gate Drivers and MOSFETs
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power MOSFETs. It offers an LTC-proprietary technique
Supports Phase Shedding and N+1 Phase
that enhances the signal-to-noise ratio of the current
Redundancy
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sense signal, allowing the use of inductors with very low
Programmable DCR Temperature Compensation
n DC winding resistances as the current sense element for
0.75% Maximum Total DC Output Error Over
maximum efficiency and reduced jitter.
Temperature
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Dual Differential Remote Output Voltage Sense
The maximum current sense voltage is programmable
Amplifiers
from 10mV to 30mV. High speed, low offset remote sense
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Phase-Lockable Fixed Frequency Range: 200kHz to
differential amplifiers and a precise 0.6V reference provide
1.2MHz
accurate output voltages between 0.6V and 3.5V from a wide
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V Range: 4.5V to 38V
IN
4.5V to 38V input supply range. Soft recovery from output
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V Range: 0.6V to 3.5V
OUT
shorts or overcurrent minimizes output overshoot. Burst
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Supports Smooth Start-Up into Pre-Biased Outputs
Mode operation, continuous and pulse-skipping modes
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Programmable Soft-Start or V Tracking
OUT are supported. The constant operating frequency can be
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Hiccup Mode/Soft Recovery from Output Overcurrent
synchronized to an external clock or linearly programmed
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36-Lead (5mm 6mm) QFN Package
from 200kHz to 1.2MHz. Up to six LTC3774 controllers can
be paralleled for 1-, 2-, 3-, 4-, 6-, 8- or 12-phase operation.
APPLICATIONS
The LTC3774 is available in a 36-lead (5mm 6mm) QFN
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Computer Systems
package.
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Telecom and Datacom Systems
L, LT, LTC, LTM, Linear Technology, the Linear logo, PolyPhase and Burst Mode are registered
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Industrial Equipment trademarks and No R and Hot Swap are trademarks of Analog Devices, Inc. All other
SENSE
trademarks are the property of their respective owners. Protected by U.S. Patents, including
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DC Power Distribution Systems
5481178, 5705919, 5929620, 6177787, 6580258, 6498466, 6611131, patent pending.
TYPICAL APPLICATION
High Efficiency Dual Phase 1.5V/60A Step-Down Converter
V
IN
4.5V TO 20V
22F
V
IN
50V
RUN1, 2 PHSMD
1/4 INTV
CC
ILIM1, 2 CLKOUT
HIZB1 PGOOD1,2
0.33H f 0.33H
HIZB2 MODE/PLLIN
IN
(0.32m DCR) LTC3774 500kHz (0.32m DCR)
DRMOS PWM1 PWM2 DRMOS
PWMEN1 PWMEN2
GND
V V
OSNS1 OSNS2
+ +
SNSA1 SNSA2
SNS1 SNS2
+ +
SNSD1 SNSD2
15k FREQ
V
OUT
+ +
V V 1.5V
OSNS1 OSNS2
I I
TH1 TH2 60A
TK/SS1 TK/SS2 INTV
2200pF CC
+ 10k
+
300F 330F
37.5k
15k
4V 4V
0.1F 4.7F
3774 TA01a
3774fc
1
For more information www.linear.com/LTC3774LTC3774
ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION
(Note 1)
TOP VIEW
V Voltage ................................................. 0.3V to 40V
IN
HIZB Voltage .............................................. 0.3V to 40V
RUN, PGOOD, INTV Voltage ..................... 0.3V to 6V
CC
+ + +
SNSA1 , SNSA2 , SNSD1 ,
36 35 34 33 32 31 30 29
+
SNSD2 , SNS1 , SNS2 ........................0.3V to INTV
CC
ITEMP2 1 28 ITEMP1
INTV Peak Output Current ..................................20mA
CC
ITH2 2 27 ITH1
All Other Pin Voltages ...........................0.3V to INTV
V 3 26 V
CC OSNS2 OSNS1
+ +
V 4 25 V
Operating Junction Temperature Range
OSNS2 OSNS1
TK/SS2 5 24 TK/SS1
(Note 2) .................................................. 40C to 125C
37
HIZB2 6 23 HIZB1
GND
Storage Temperature Range .................. 65C to 150C
PWMEN2 7 22 PWMEN1
PWM2 8 21 PWM1
RUN2 9 20 RUN1
GND 19 GND
10
11 12 13 14 15 16 17 18
UHE PACKAGE
36-LEAD (5mm 6mm) PLASTIC QFN
T = 125C, = 43C/W
JMAX JA
EXPOSED PAD (PIN 37) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION